reverse problem

yui0329 · April 23rd, 2005, 09:39 AM

Modify the following code, write a method "Reverse(char[] s1, char[] s2)", ths string s1 and s2 must be the same size, the string s1 should become a reverse copy of string s2. Internal to reverse, use the CharStack to perform the reversal.

using System;

public class CharStack
{
private const int EMPTY = -1;
private int maxLen;
private char[] s;
private int top;
public void SetStack(int maxSize)
{
s = new char[maxSize];
maxLen = maxSize;
top = EMPTY;
}
public void Reset() { top = EMPTY; }
public void Push(char c) { s[++top] = c; }
public char Pop() { return s[top--]; }
public char TopOf() { return s[top]; }
public bool Empty() { return (top == EMPTY); }
public bool Full() { return (top == maxLen - 1); }
}
class CharStackTest
{
public static void Main()
{
CharStack s = new CharStack();
string str = "My name is Don Knuth!";
char[] reStr = new char[str.Length];
int i = 0;
s.SetStack(str.Length); // stack can accommodate str
Console.WriteLine(str);
while ((i < str.Length) && !s.Full())
s.Push(str[i++]);
while (!s.Empty()) // print the reverse

Console.Write(s.Pop());
Console.WriteLine();
}
}

Imar · April 24th, 2005, 02:59 AM

What's this? Are you sharing useful code, or do you want us to do your homework?

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

yui0329 · April 24th, 2005, 06:44 AM

Same in this one, I couldn`t do the question, please help.

mehdi62b · April 25th, 2005, 05:56 AM

well,have a look at the codes,

Code:

        private void reverse(char[] s1,char[] s2)
        {
            if(s1.Length!=s2.Length)
                throw new Exception("the lenghts should be equal");
            CharStack stack=new CharStack();
            stack.SetStack(s1.Length);
            foreach(char ch in s1)
                stack.Push(ch);
            for(int i=0;i<s2.Length;i++)
                s2[i]=stack.Pop();
        }
        private void ToUse()
        {
            string name="My name is Don Knuth!";
            char[] s2=new char[name.Length];
            this.reverse(name.ToCharArray(),s2);
            foreach(char ch in s2)
                textBox1.Text+=ch.ToString();
        }

_____________
Mehdi.
software student.

yui0329 · April 25th, 2005, 07:52 AM

I got it, thank you very much!!

mehdi62b · April 25th, 2005, 08:12 AM

no problem,
it's better to change the CharStack class

Code:

    public class CharStack
    {
        private const int EMPTY = -1;
        private int maxLen;
        private char[] s;
        private int top;
        public CharStack(int maxSize)
        {
            s = new char[maxSize];
            maxLen = maxSize;
            top = EMPTY;
        }
        public void Reset() { top = EMPTY; }
        public void Push(char c)
        {
            if(!this.Full())
                s[++top] = c;
            else 
                throw new Exception("stack is full");
        }
        public char Pop() 
        {
            if(!this.Empty())
                return s[top--];
            else 
                throw new Exception("stack is empty");
        }
        public char TopOf() { return s[top]; }
        public bool Empty() { return (top == EMPTY); }
        public bool Full() { return (top == maxLen - 1); }
    }

instead of SetStack you can have a constructor also when you want to pop or push something you should check the stack.

_____________
Mehdi.
software student.